How do I shatter rigid bodies on edges
There are a bunch of very good fracture add-ons out there. Some of them only support fracturing the entire object at one time, while others actually let you control the places that the object fractures. You may want to consider this add-on as it lets you do that kind of thing with objects. I am positive that there is no way to automatically generate fractured edges based off of the rigid-body simulation, but this add-on should help a lot.